Compression release for internal combustion engines



D. E. WEIGLAGE ET AL July 11; 1967 3,330,263 COMPRESSION RELEASE FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet l Filed Feb.

INVENTORS WEGLHGE DAVID E. BY ALBERT H. WEGLHGE July 11, 1967 D WEGLAGE ET AL 3,330,263

COMPRESSION RELEASE FOR INTERNAL COMBUSTION ENGINES Filed Feb. 1967 5 Sheets-Sheet 2 l I I 5 I; INVENTORS ID E. h/EGLHGE HLBERT H. WEGLHGE July 11, 1967 D E, WEGLAGE ET AL 3,330,263

COMPRESSION RELEASE FOR INTERNAL COMBUSTION ENGINES Filed Feb. 6, 1967 3 Sheets-Sheet Z INVENTORS DAVID E. WEGLHGE BY ALBERT H. Ll/EGLHGE United States Patent 3,330,263 COMPRESSION RELEASE FOR INTERNAL COMBUSTION ENGINES David E. Weglage and Albert Weglage, Dayton, Ohio, assignors of one-third to Walter Becker, Dayton, Ohio Filed Feb. 6, 1967, Ser. No. 614,203 21 Claims. (Cl. 123-182) The present invention relates to internal combustion engines and, more specifically, concerns the manual starting of such engines.

This application is a continuation-in-part application of our co-pending application Ser. No. 547,503, filed May 4, 1966.

The manual starting of internal combustion engines, particularly those used in connection with garden and horticultural implements such as lawn mowers, snow blowers, pumps and the like has been quite some problem and, therefore, various attempts have been made to facilitate the manual starting of such engines by releasing the compression during the starting of the respective engine.

Most of the heretofore known so-called compression release devices designed for facilitating purely manual starting of internal combustion engines are either based on a permanent change of the cam controlling the inlet or outlet valve or on the employment of an auxiliary cam for controlling the respective valve. The permanent change in the cam contour is such that during the compression stroke the respective valve is held open longer than normally thereby bringing about a permanent loss of compression. In order to maintain this loss within permanent limits, the permanent change in the cam contour of this known arangement is such as to cause a rather slight compression release movement only of the valve, and to this end requires very close tolerances. If these tolerances are not met, the said device is practically ineflicient.

The arrangements employing an auxiliary cam have this cam designed similar to the first mentioned cam so that the respective valve will be held open longer than normally,

and rely on centrifugal force to make the auxiliary cam ineffective and to permit the normal cam to control the valve. While this last mentioned device avoids permanent loss of compression during the ordinary running operation of the engine, it is rather expensive in view of the elements involved. The auxiliary cam, however, must likewise be so designed as to permit the valve to close during one revolution of the cam. In other words, the auxiliary cam fundamentally works in the same way as in the compression release device with permanently modified cam contour and thus has the very same drawback with regard to the limitations concerning the possible compression release during the starting operation.

In our co-pending application Ser. No. 480,086 filed Aug. 16, 1965, (now Patent No. 3,307,527), there has been disclosed a compresison release mechanism which in contrast to the above identified compression release devices is completely independent of the contour of the valve controlling cams and thus is completely independent of the cams with regard to the extent to which the respective valve for purposes of compression release may be held open. Moreover, the compression release device set forth in our said co-pending application employs a new principle. for making the compression release ineffective during the normal running of the engine, namely by using for this purpose the gaseous flow from the crankcase to the spring chmiber occurring during the operation of the engine.

It is an object of the present invention further to simplify the compression release device set forth in our above mentioned co-pending application so as to be able to avoid any fine tolerances with regard to any elements used in the compression release system itself.

It is a further object of this invention to provide an improved compression release device in which the elements involved are of an extremely simple structural nature thereby avoiding any costly and complicated dies while permitting an extremely low cost manufacture.

Still another object of this invention consists in the provision of a compression release device as set forth in the two preceding paragraphs, which can easily be installed, even in older engines.

It is a still further object of this invention to provide a compression release device of the type set forth in the preceding paragraphs, which will not be affected by tolerances, i.e. which will fit into any engine for which it has been generally designed, regardless of the manufacturing tolerances of the specific engine to be outfitted with the compression release device.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a vertical section through a customary one cylinder four stroke cycle internal combustion engine arranged horizontally, as it is used for various purposes, for instance in connection with horicultural equipment, said engine being shown equipped with a compression release arrangement according to the present invention while the section through the portion provided with said compression release device is taken along the line II of FIG. 2.

FIG. 2 is a section along the line 11-11 of FIG. 1.

FIG. 3 represents a section taken along the line IIIIII of FIG. 2.

FIG. 4 illustrates an exploded view of the compression release mechanism proper.

FIG. 5 shows a slight modification of the compression release shown in FIG. 1 inasmuch as the compression release lever has one of its arms bent differently for application in a vertical engine.

FIG. 6 is a vertical section through a customary upright one cylinder four stroke cycle internal combustion engine similar to that of FIG. 1 with a modified compression release device which in contrast to the compression release device of FIG. 4 consists of only two pieces united to a single unit, said compression release device being shown in its effective position.

FIG. 7 is a section along the line VII-VII of FIG. 6.

FIG. 8 is a section through the spring chamber along the line VIII-VIII of FIG. 7.

FIG. 9 is an isometric view of the compression release device of FIGS. 6-8.

FIG. 10 shows a portion of FIG. 6 with the compression release device of FIG. 6 in its non-effective position which it occupies when the engine is idling or in normal operation.

'FIG. 11 is a section through the spring chamber similar to that of FIG. 8, but with a modified compression release device.

FIG. 12 is a section taken along the line XII-XH of FIG. 11.

FIG. 13 is an isometric view of the compression release employed in FIGS. 11 and 12.

FIG. 14 is an isometric view similar to that of FIG. 13 of a modified compression release device according to the invention, which differs from that of FIG. 13 primarily as to the shape of the lever or wire.

The present invention is characterized primarily by a cranked lever, preferably a cranked wire, pivotally journalled in the spring chamber of the engine between the valve stems or push rods of the inlet and outlet valves and having one arm extending into or across the passage through which customarily gaseous flow passes from the crankcase into the spring chamber from where said gaseous fiow'is released e.g. into the atmosphere. The crank or crank arm of the said lever is adapted to move into 3 and out of the path of the spring dish means of one of the valves.

Referring specifically to the drawing, the internal com- 7 bustion engine illustrated therein which may be of the general type shown in FIG. 1 of our co-pending application Ser. No. 480,086 above referred to, is shown in FIG. 1 by way of example as a horizontal engine. The internal combustion engine shown in the drawing comprises a cylinder block 1 with a cylinder 1a. Mounted on cylinder block 1, in customary manner, is a cylinder head 1b. Cylinder block 1 comprises a spring chamber 2 'Whichhas connected thereto a housing or crankcase 3. J'ournalled to said housing 3 is a cam shaft 4 which is drivingly connected to the crank shaft (not shown) of the engine in a manner customary with four-stroke cycle internal combustion engines through gears. As is also well known in the art, the cylinder 2 has reciprocably mounted therein a piston (not shown) which is drivingly connected to the crank shaft.

Likewise in customary manner, cam shaft 4 is provided with a first cam 5, and a second cam 6. Cam 5 normally,

'i.e. during idling or the ordinary driving operation of.

the engine, is in continuous engagement with a lifter 7 having a litter shank 7a which in turn engages the stem 8 of the exhaust valve 9 controlling the connection of the engine cylinder with an exhaust port (not shown) through a pass-age 10. As will be seen from FIG. 1, that portion of valve stem 8 which extends into spring chamber 2 is surrounded by a valve spring 10 having one end resting against spring chamber wall 11. The other end of spring 16 rests against a spring keeper 12 holding spring 10 under preload and being held in its position on one hand by spring 10 and on the other hand by a C-clamp 13 (see also FIG. 4) which rests in a recess 14 of spring keeper 12 and engages a groove 8a in valve stem 8. As will be evident from the above, spring 10 continuously urges valve 9, shown in an open pressure releasing position, into its closing position. Cylinder block 1 furthermore, in customary manner, comprises a litter 15 controlled by cam 6 on cam shaft 4. Cam 6 in turn through lifter shank 15a and valve shank 16 controls the inlet valve 17 which latter controls a passage 17a communicating with a fuel supply passage 17b. Similar to the outlet valve 9, also the inlet valve 17 is provided with a spring 18 located in the spring chamber 2, a spring keeper 19 and a C-clamp 20 holding spring 18 under preload, said spring 18 continuously urging inlet valve 17 into closing position.

In conformity with the standard design of four-stroke cycle internal combustion engines employed for agricultural and horticultural implements such as lawn mowers, the spring chamber 2 communicates with the interior of the housing or crankcase 3 through a passage 21 through which during the operation of the engine a gaseous flow occurs from the crankcase to the spring chamber 2 from where it is released e.g. through a breather plate of any standard design for instance of the type shown in FIGS. 12 and 12a of our above mentioned copending application Ser. No. 480,086. Such breather plate B is also shown in view in FIGS. 7, 8, 11, and 12 of the drawings in the present application. a

While the diameter of said passage 21 may vary with various designs, in conformity with the requirement for releasing the gaseousrflow from the crankcase 3 and pas .sage 21 into the spring chamber 2 and from there e.g.

through the breather device into the atmosphere, it is to be noted that no change in the diameter of the piston "and the said passage 21 of the standard engine is necessary for the present invention, and that any change thereof will not change the principle of the present invention. As a matter of fact, it is very easy to equip any standard four-stroke cycle internal combustion engine later with a pressure release device according to the present invention regardless of the size of the piston and the said passage 21.

The arrangement described so far is substantially standhas a fairly long hub 12a which engages valve stem8 with slide fit so as to be properly guided thereon. That side of spring keeper 12 which faces away from spring chamber wall 11 is provided with a recess 14 which receives the C-clamp 13 against which rests one end of a small preloaded spring 22 which in the position shown in FIG. 1 surrounds valve stem 8 and lifter shank 7a- That end 'of spring 22 which is remote from spring keeper 12 rests on a plate 23 (FIGS. 1, 2 and 4). The said plate 23 is provided with two bores 24 and 25 through which lifter shanks 7a and 1501 respectively pass with slide fit. In

addition thereto, plate 23 is provided with a third bore 26. That side of plate 23 which rests on the bottom wall 27 of spring chamber 2 is provided with a transverse groove 28 which preferably has a slightly rounded bottom for a purpose which will presently appear. As will be seen best from FIGS. 1, 3 and 4, a cranked compression release lever 29 in' the form of a wire has two relatively short arms 30 and 31 journalled in the transverse groove 28 of plate 23, and since spring 22 and a similar spring 32 (the latter being arranged between plate 23 and spring keeper 19) firmly hold plate 23- against the bottom wall 27 of spring chamber 2, and the arms 30 and 31 of compression release lever 29 are firmly pivotally journalled in groove 28.

As will furthermore be seen from FIGS; 1, 3 and 4, compression release lever 29 has a cranked portion 33 which extends through bore 26 and can move therein from the full line position shown in FIG. 1 to the dash will appear more clearly from the operation. The main point is that section 34a must be long enough to pass through bore 25 and that arm section 34b will, when in its dash-line position, occupy such a location that the cranked portion 33 has moved over to such an extent away from the axis of stem Sand shank 7i: as to permit spring 10 to push valve stem 8 and lifter shank 7a in the direction toward cam 5 so that lifter 7 will at all times be in engagement with cam 5. Furthermore, the center of gravity of lever 29 must be so located that lever 29, when not held in its dash-line position will by gravity move into its full-line position as soon as spring keeper 12 has moved sufiiciently toward the left with regard to FIG. 1. From the above, it will also be clear that arm section 34b is bent with regard to arm section 34a somewhat in the direction in which the airflowiug toward bore 26 will tilt lever arm section 34b to move the cranked section 33 into its inefiective position.

Operation of'arrangement of FIGS. 1-4 It may be assumed that the engine a Portion of which is shown in FIG. 1 and which by way of example is as sumed to be a 4-stroke single cylinder lawn mower eugine with horizontally extending lifter and valve shanks, Is at a standstill. In this position, the compression release or control lever 29 is in its solid position shown in FIG.

l which represents its effective or compression releasing position. In this position, the cranked portion 33 of said compression release lever keeps the spring keeper 12 in.

valve stem 8 to push lifter 7 into engagement with cam 5 when the latter occupies its position shown in FIG. 1. On the other hand, lifter 7 due to its horizontal position does not by itself slide back into engagement with cam 5. Merely by way of example, the valve 9 may in its compressing releasing position be open by .060". However, it should be noted that this value is given merely by way of example and that, if desired, this opening can be even greater.

When the crank shaft is now manually turned for starting the engine, for instance by means of a pulley connected to the crank shaft and a rope extending around the pulley, as is standard in numerous lawn mower engines, the immediate movement of the piston and of the crank shaft creates a gaseous flow from the crankcase to the spring chamber 2 through bore 21. Spring chamber 2 is vented by breather means referred to above. On its way from the crankcase through bore 21 into spring chamber 2, said gaseous flow impinges upon the lever section 3412 and moves the same in counter-clockwise direction as soon as cam 5 by its higher cam face 5a lifts lifter 7 and thereby valve 9 beyond its opening position shown in FIG. 1 and thus also lifts spring keeper 12 so that the cranked portion 33 of lever 29 can move into its dash line position, i.e. away from valve stem '8 and lifter shank 7a. The momentum which the movable components of the engine gain during the initial starting phase in view of the fact that valve 9 at the very start of the starting operation was held relatively wide open by the compression release lever 29 is fully sufiicient to move the piston through its next following compression stroke, and as a rule the engine will start. This means that the engine will operate at an even higher speed, and the said gaseous flow through passage 35 will be more than sufficient to hold lever 29 in its inelfective position.

However, if the engine should not start, the speed of the engine will immediately decrease and, consequently, the said gaseous flow through passage 35 will drop to such an extent that the lever 29 will by its own weight assume the position in FIG. 1 as soon as during the upward stroke of lifter 7 the cranked portion 33 is free to move below spring keeper 12 in which instance the solid position of control lever 29 is restored and a new starting operation of the engine can be effected with the compression release fully effective as before. Sirnilarly, when after running the engine for a period of time, the latter is turned off, shortly before the engine comes to a standstill, the said gaseous flow from the crankcase to the spring chamber decreases to such an extent that the control lever will move back to its effective position as outlined above. In this way, the compression release is always elfective when the engine is to be started. Similarly, the compression release remains ineffective throughout the normal operation of the engine including its idling phase so that there will be absolutely no compression loss during the normal operation of the engine during which the engine will operate as if there were no compression release mechanism at all present.

For the sage of completeness, it may be mentioned that according to the specific showing in FIG. 1, the compression release lever extends into a channel 35 which is formed in many standard engines as a reinforcement for the crankcase and by a reinforcement of the spring bottom portions through which the valve shanks extend. However, for the function of the compression release according to the present invention, this passage is not necessary since as soon as the above mentioned gaseous flow from the crankcase to the spring chamber through bore 21 has built up, it impinges upon the compression release lever in the manner outlined above.

It will also be evident from the above, that the total length of the two lever sections 34a and 341) should be such that the lever 29 will by gravity always tend to I occupy the position shown in solid lines in FIG. 1. Furthermore, the angle between the sections 34a and 34b,

as mentioned above is not limited to the specific angle shown in the drawing but may vary to a considerable extent. The main point is that the air can pass bet-ween the spring chamber bottom wall 27 and the section 34b so as to tilt lever 29 in the above outlined manner.

Modification of FIG. 5

The arrangement of FIG. 5 substantially corresponds to that of FIG. 1 with the exception that the compression release lever 29b is bent in the opposite direction with regard to'lever 29 inasmuch as the compression release mechanism shown in FIG. 5 is applied to an upright engine. The various elements appearing in FIG. 5 and corresponding to those of FIG. 1 therefore have been designated with the same reference numerals as in FIG. 1. Also the operation of the compression release mechanism shown in FIG. 5 is the same as that described in connection with FIGS. 1 to 4. In other words, when the higher cam face of cam 5 lifts lifter 7, while the said gaseous flow from the crankcase 3 through passage 21 into spring chamber 2 occurs, the said gaseous flow impinging upon the compression release lever 2% will move the same in counter-clockwise direction and thereby pull the crank from below spring keeper 12 from its full line position into its dash position shown in FIG. 5 as soon as the spring keeper is sufficiently lifted by cam 5 and lifter 7. Gn the other hand, when the engine after a running period slows down in order to come to a stop, lever 2912 will by gravity be moved from its dash line position into its full line position with the crank 33b below spring keeper 12. While in FIG. 5 the lever section 34b has its end resting on the bottom wall of passage 35a, it will be understood that this is not necessary, and that the full line position of lever 2% could also be arrested by the crank 33]) hitting the edge of the hole through which it extends. Similar remarks also apply incidentally to lever 29 in FIG. 1 with regard to its dash line position.

Modification of FIGS. 6-9

FIG. 6 is a vertical section through an upright onecylinder four-stroke cycle internal combustion engine with a modified compression release device according to the invention which compression release device is shown by itself in isometric view in FIG. 9. Since the structure of the upright one-cylinder four-stroke cycle internal combustion engine of FIG. 6 is the same as that of FIG. 1 with the only difference that it is an upright engine whereas FIG. 1 shows a horizontal engine, similar parts in FIG. 6 have been designated with the same reference numeral as in FIG. 1. However, as mentioned above, the compression device employed in the engine of FIG. 6 is greatly simplified over that of FIG. 1 in construction, in assembly and disassembly. The compression release device used in FIG. 6 is best shown in FIG. 9 and comprises only two parts, namely, a stamping 36 and a wire 37. The stamping 36 comprises a bottom portion 36a with upwardly bent low side walls 36b and 360 and with an upwardly bent tongue 36d. In addition thereto, the stamping 36 has a tongue 36e in approximately the same plane as the bottom 36a. Furthermore, the stamping 36 is provided with eyes 36f and 36g which serve as bearing for the wire 37. Finally, the stamping 36 has a bent resilient portion 36-h. The wire 37 has a crank portion 37a and has two arms 37b and 37c which are at an angle to the intermediate wire section 37d which contains the crank 37a.

As will be seen from FIG. 6, the bottom wall 27 of spring chamber 2 is provided with two bosses 38 and 39 through which the lifter shanks 7a and 15a extend. As shown in FIGS. 7, 8, and 10, the compression release device of FIG. 9 is pushed into the spring chamber 2 between the bosses 38 and 39 so that the upper portion of the slightly resilient upwardly bent tongue 36d resiliently engages the top wall 11 of the spring chamber 2 while the side wall 36b and the bent resilient portion 36h en- "Z gage those sides of the bosses 38 and 39 which face each other. Finally, the outer end of tongue -36e which is likewise slightly resilient, is engaged by the breather plate B connected to the cylinder block by screws 40. It will be evident from the above that in this way the stamping 36 which may consist of sheet metal is firmly located and held in the spring chamber 2 whereby also the wire 37 is held in a definite location. When the compression release device D of FIG. 9 is thus fully inserted and located in spring chamber 2, and occupies its effective or compression releasing position, the crank portion 37a,

*similar to the crank portion 33 of the embodiment of FIGS. 1 to 4 and the crank portion 33b of the embodiment of FIG. 5 is located below the spring keeper 12 thereby holding valve 8 in its open or compression releasing position in a manner similar to that described in connection with the embodiment of FIGS. 1 to 4. At the same time the wire arm v37b lies on the bottom wall 27a of the spring chamber 2 as shown in FIG. 6, while a portion of the arm 37b lies over the passage 21.

In other words, contrary to the embodiment of FIGS. 1 to 5 the wire arm 37 does not extend into and through the passage 21, but lies across the same. In this position of the wire 37, which, as mentioned before, is shown in FIG. 6, the arm 37c extends at a slight incline. The arm 37c acts as a kind of control arm, since its length influences the sensitivity of the movement of arm 37b by the flow through passage 21.

Operation of the modification of FIGS. 6-10 The operation of the arrangement shown in FIGS. 6 to 10 substantially corresponds to the operation of the arrangement of FIGS. 1 to 4.

Assuming that all elements of the engine shown in the drawing occupy the position in full lines in FIG. 6, it will be noted that the cranked wire portion 37a keeps the spring keeper 12 in raised position so that the valve 9 occupies its compression releasing position, while the lifter shank 7a is spaced from the valve stem 8. The opening of valve 9 may, for instance, be the same as shown by way of example in FIG. 1.

When the crank shaft is now manually turned for starting the engine, for instance, in the same manner as assumed in connection with the embodiment of FIGS. 1 to 4, the immediate movement of the crank shaft creates a gaseous flow from the crank case to the spring chamber through bore 21 in the same manner as described above in the embodiment of FIGS. 1 to 4, and this gaseous flow impinges upon the wire arm 37 b and tilts the same in counterclockwise direction with regard to FIG. 6. Since the crank 37a moves out from below the spring keeper 12, spring 10 through spring keeper 12 moves valve stem 8 into engagement with lifter shank 7a, and the compression release device has become ineffective while the momentum gained by the movable components of the engine during the initial starting phase will be sufficient to move the piston through its next following stroke, and as a rule the engine will start. Thus, the operation of the embodiment of FIGS. 6 to 10 is fully analogous to that of FIGS. 1 to 4, the only difference being'in the specific design and great simplification of the compression release device D shown in FIG. 9.

Modification of FIGS. 11-13 The compression release device shown in FIG. 13 is a further simplification over the compression release device of FIG. 9. More specifically, the device of FIG. 13 likewise consists of a stamping 41 of sheet metal which also has an extension 41a which corresponds somewhat to the extension 36d of FIG. 9, but is slightly differently shaped at the outer end. Furthermore, the stamping 41 F is provided with cutouts 41b and 41c which take the.

place of the bores 24 and 25 in the embodiment of FIG. 4. The upper edge (with regard to FIG. 13) 0f the stamping 41 has a folded over portion 41d which forms the 'bearing for a wire 42. This wire, in contrast to the wires namely, merely a wire arm 42a for the same purpose as the above mentioned cranks'33 and 37d.

The stamping 41 is furthermore provided with a slot I 41, the width of which substantially corresponds to the diameter of the wire 42. The slot 412 extends over a portion only of the opening through-which passage 21 leads into the spring chamber 2. The remaining portion of the said opening is covered by the stamping 41. In this way the effective opening is somewhat reduced with the result that the gaseous flow which passes during the operation of the engine from the crankcase into 'the spring chamber exerts a kind of jet force upon the wire.

The tilting movement of the wire arm or, crank 42a in counterclockwise direction with regard to FIG. 13, is limited by abutment of the arm or crank 42a with a tongue 41 at the edge portion adjacent to the folded over portion 41d. This limitation of the tilting movement will assure that the lever arm 42b, 42c, 42d, will always-retain a position in which the force of gravity acting thereupon will always tend to move said lever arm in clock wise direction with regard to FIG. 13 to thereby make sure that the wire 42 occupies its full line or efiective position in FIG. 13 before the engine comes to a total stop.

The movement of crank 42a in clockwise direction with regard to FIG. 13 is limited by the wire arm 42b which is longer than slot 41e and engages the adjacent major surface 420 of the. stamping 41. The arm 42b has an extension 42d, which when the arm 42b engages the major surface 420 of the stamping 41 is, due to the crank 42e in the wire 42, spaced from the surface 420.

The fact that the movement of crank 42a in clockwise direction with regard to FIG. 13, is limited by the engagement of wire arm 42b with the surface 42c of stamping,

its elfective position, crank arm'42a'is preferably slightly inclined similar to arm 37a in FIG. 6.

It will also be appreciated that when the stamping 41 is in the upright position shown in FIG. 13, the weight of the wire portion comprising the arm sections 42b, 42e, and 42d will tend to move the wire 42 into the position shown in FIG. 13. On the other hand, if the stamping 41 were tilted from its upright position in FIG. 13 into a horizontal position so that the surface 420 were located in a horizontal plane, the weight of the arm sections 42b, 42e, and 42d would again tend to move the lever 42 so that the arm 42b would partially engage the surface 420. Thus, the arrangement of FIG. 13 ,can be used equally well without any change for both horizontal engines and vertical engines. I

The mounting of the compression release device of FIG- 13 will easily be understoodfrom a'view at FIGS.

11 and 12. As will be seen from these figures, it is merely necessary, after removal of the breather plate B by unscrewing the screws 40 to push the compression release bottom 44 of the spring chamber, which bottom in con-' trast to the bottom 27 of FIG. 1 is slightlyinclined, and

in contrast to the bottom 27a of FIG. 6 does not have bosses 38, 39. It will be understood, however, that if a spring chamber of the type shown in FIG. .6 were to'be.

equipped with the compression release device of FIG. 13, the sheet metal stamping-41 would have to have the slots 41b, 41c enlarged so that the slots 41b and 41cfit around the bosses 38, 39. It will also be noted from FIG. 11, that the width of the slots 41b, 41c and also the inner ends thereof, are slightly spaced from the outer periphery of the lifter shanks 7a, a so that the stamping 41 will not be engaged by the moving lifter shanks 7a, 15a. When the compression release device, according to FIG. 13 has been pushed into the spring chamber 2, as shown in FIGS. 11 and 12, the tongue 41a will engage the ceiling or top 11 of the spring chamber 2, and, due to its resiliency will firmly press and hold the stamping 41 in its position. It is then merely necessary to place the breather plate B again into its previous position, as shown in FIGS. 11 and 12, in which the inner portion of the breather plate engages the arm 41h of the extension 41a thereby likewise holding the compression release device in its position.

When the compression release device of FIG. 13 is properly installed and the engine is at a standstill, the crank arm 42a occupies a position below the spring keeper 12, as shown in FIG. 12, so as to hold the same in an elevated position in a manner similar to that described in connection With FIGS. 1 to 10 whereby the valve pertaining to the valve shank 8 is in its compression relieving position. When the movable elements of the engine are in motion so that gaseous flow passes from the crank .case through the passage 21, the said gaseous flow will in the same manner as described with previously mentioned embodiments of this invention tilt the wire 42 in counterclockwise direction with regard to FIG. 13 to thereby move the crank arm 42a out from below the spring keeper 12 as soon as the lifter shank 7a during the normal revolution of the cam shaft has raised the valve shank 8 and thereby the spring keeper 12 sufficiently to free the free end of crank 42a.

In other words, the operation of the compression re-' lease device of FIG. 13 fully corresponds to the operation of the compression release devices disclosed in connection with FIGS. 1 to 10, and in the instance of the compression release device of FIG. 13, the same compression release device can be used for horizontal as well as for vertical engines.

Referring now to FIG. 14, the compression release device shown therein is very similar to that of FIG. 13 with the exception that the tongue or stop 41] of FIG. 13 is eliminated and that the lever 42 of FIG. 13 has been replaced by a differently shaped lever 45. This lever 45 has its portion 45a replacing the sections 42c and 42d of lever 42 in FIG. 13, bent backwardly so that when the crank arm 45b is in its ineffective position, the outer end of the arm portion 45a will be in engagement with the spring chamber 46 (see also FIG. 11), which wall, in this instance, acts as a stop for the lever arm portion 45a. It will be appreciated that when the end of lever portion 45a engages the spring chamber wall 46, the lever 45 occupies a position in which its center of gravity is so located that the lever 45 will return to its ineffective position as soon as the gaseous flow through the slot 45d is no longer sufiicient to lift the lever portion 452 out of slot 45d and off the surface 45] of the compression release device shown in FIG. 14, so that crank arm 4512 will again be in its etfective position.

The insertion of the compression release of FIG. 14 and its operation fully corresponds to that of FIG. 13.

It may also be mentioned that in some cases in which the taper in the spring chamber, which taper is customarily provided for casting purposes, is rather pronounced, the outer end of the tongue portion 41a in FIG. 13 and of the tongue portion 45g in FIG. 14 may be bent slightly toward the surface 420 and 45f respectively to facilitate the insertion of the compression release.

From the foregoing description, it will be noted that the compression release devices set forth therein are easily adapted to various engine designs and can be installed therein without requiring any structural changes of the engines to be equipped with the respective compression release device. Thus, engines of the type involved lacking compression release devices, can easily be equipped with a compression release device according to the invention.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings, but also comprises any modifications within the scope of the appended claims.

It is, furthermore, to be understood that while the spring keeper 12 shown in the drawings has proved particularly suitable in connection with the present invention, the compression release according to the present invention is, by no means, limited to the employment of such spring keeper. As a matter of fact, numerous tests of the compression release devices according to the present invention in engines with standard spring keepers have proved highly successful.

What we claim is:

1. An internal combustion engine having a cylinder block with spring chamber means, a crankcase connected to said cylinder block, a crank shaft rotatably journalled in said crankcase, conduit means establishing communication between the interior of said crankcase and the interior of said spring chamber means for conveying a gaseous flow occurring during the operation of said engine and passing from said crankcase into said spring chamber means, and means for venting said spring chamber means, which includes: inlet and outlet valve means controlled by said crank shaft, each of said valve means being movable into a closing and opening position and vice versa and having a valve stem extending into said spring chamber means, lifter means operable by said crank shaft and extending into said spring chamber means for cooperation with said valve stems, spring keeper means respectively surrounding and being supported by said valve stems, preloaded spring means operatively connected to said spring keeper means and continuously urging said valve means to move to their closing positions, lever means journalled to pivot about an axis spaced from the axes of said lifter means and including a cranked portion located Within said spring chamber means and movable into the path of movement of one of said spring keeper means to prevent the latter and thereby the valve stem carrying the same from completing its normal stroke toward the lifter means cooperating therewith whereby the respective valve means remains open, said cranked portion also being movable out of the path of movement of said one spring keeper means to thereby permit the latter and thus the valve means pertaining thereto to move into its closing position in conformity with the movement of said cam shaft, said lever means having arm means extending into the path of the gaseous fiow passing from said crank case through said conduit means into said spring chamber means during the operation of said engine, said lever means being so designed and journalled as to be continously urged by gravity to move into the path of movement of said one spring keeper means and also being adapted by said gaseous flow from said crankcase to said spring chamber means at engine idling speed and above the same to be moved in a direction opposite to the lever movement by gravity and against the force of gravity acting upon said lever means.

2. An internal combustion engine according to claim 1, in which said lever means is formed by a wire.

3. An internal combustion engine according to claim 1, which includes plate means provided with an opening permitting the movement therein and passage therethrough of said cranked portion of said lever means, said plate means being mounted on that wall portion of said spring chamber means which defines one end of said conduit means, that surface of said plate which faces said last mentioned wall portion being provided with groove means extending along a diameter line of said opening and journalling said lever means.

4. An internal combustion engine according to claim 1, in which said plate is located by said lifter means, and preloaded spring means interposed between said spring ll keeper means and said plate to hold the latter substantially stationary.

5. An internal combustion engine according to claim 1, in which said one spring keeper means has a relatively long hub portion engaging the valve stem surrounded thereby with slide fit to thereby prevent said one spring keeper means from tilting toward the axis of the valve stem surrounded thereby.

6. An internal combustion engine according to claim 3, in which said lever means has two aligned arms pivotally journalled in said groove means and also has two additional arms forming. an obtuse angle with each other, one of said additional arms extending through said conduit means into said crankcase while the other one of said additional arms is located in said crankcase outside said conduit means. a

7. An internal combustion engine according to claim 1, which includes supporting means mounted on that wall of said spring chamber means through which saidlifter means extend, said lever means being journalled on said supporting means so as to form a unit therewith, said lever means having its said arm means extending above the opening through which said conduit means leads into said spring chamber means when said cranked portion is in thepath of movement of said one spring keeper means.

8. An internal combustion engine according to claim 7, in which said supporting means has an extension resiliently engaging that spring chamber wall other than thespringchamber wall on which said supporting means is mounted.

9. An internal combustion engine according to claim 7, in which said supporting means is formed by a plate, and in which said passage means is in the form ofa slot, that portion of said arm means which extends above said slot having approximately the same width as said slot. 10. An internal combustion engine according to claim 7, in which said supporting means is provided with a portion for insertion between the lifter means.

11. An internal combustion engine according to claim 7, in which said supporting means is provided with a stop 'for engagement with said cranked portion when the latter a has moved out of the path of movement of said one spring keeper means.

12. An internal combustion engine according to claim 7, in which said arm means extending above saidpassage means is provided with an extension curved back in the direction toward the axis of the journalled portion of said lever means and having its free end adapted to engage a spring chamber wall as a stop when said cranked portion has moved out of the path of movement of said one spring keeper means. 7

13. An internal combustion engine according to claim 7, in which the spring chamber means'comprises two spacedbosses through which respectively said lifter means extend.

14. An internal combustion engine according to claim 13, in which said supporting means has a portion inserted between said bosses for locating said plate in said spring chamber means.

15. A compression release device for insertion into the spring chamber of a four stroke cycle internal combustion engine, which comprises: supporting means including means for locating said supporting means and holding same in the spring chamber; said supporting means also being provided with a passage therethrough, and lever means turnably journalled on said supporting means so as to form a unit therewith; said lever means having an arm extending over said passage means in close relationship thereto in one positionof said lever means and being movable by a gaseous flow through said passage means away from the latter; said lever means also having a cranked portion movable from an effective position correelfective position thereof. I

' 17. A compression release device according to claim 15, inwhich said supporting means is provided with an T 16.'A compression release device according to claim 15, in which said supporting means has formed thereon stop means for stopping said cranked portion in the in- L-shaped extension having the longer leg thereof arranged adjacent said supporting meansand having the shorter leg arranged adjacent that end of said longer leg which is remote from said supporting means, said shorter leg extending in the direction of the width of said supporting means, said arm being so designed as to be continuously urged by gravity to move to said one position when said supporting means is in a horizontal position and located below said shorter leg and also when said supporting means is in a vertical position and the cranked portion of I said lever means is located at a level higher than the major portion of said arm.

18. A compression release device according to claim 15, in which said supporting means is formed by a plate,

andin which said passage means is in the form of a slot extending in the longitudinal direction of said plate, said' arm extending in the longitudinal direction of said slot and having a width corresponding substantially to the width of said slot. I

19. As an insert into the spring chamber of a fourstroke cycle internalcombustion engine having a crankcase and being provided with lifter means extending through a first spring chamber wall into said spring chamber and with valve stem means extending through a sec: ond wall of said spring chamber into the latter and carrying spring keeper means within said spring chamber While said first spring chamber wall has a passage therethrough communicating with said crankcase; a compression release unit having a supporting means adapted to be placed on said first spring chamber wall While leaving said passage open, lever means pivotally journalled on said supporting means and having a first arm movable from a first position in which it rests over said passage to a second position in which it is lifted away from said passage, said lever means also having a second arm movable from a position in the path of said spring keeper means to a position outside said path and vice versa in conformity with the movement of said first arm from said first ,to said sec- 7 axis about which said lever means is turnable.

References Cited UNITED STATES PATENTS CARLTON R. CROYLE, Primary Examiner.

RALPH D. 'BLAKESLEE, Examiner. 

15. A COMPRESSION RELEASE DEVICE FOR INSERTION INTO THE SPRING CHAMBER OF A FOUR STROKE CYCLE INTERNAL COMBUSTION ENGINE, WHICH COMPRISES: SUPPORTING MEANS INCLUDING MEANS FOR LOCATING SAID SUPPORTING MEANS AND HOLDING SAME IN THE SPRING CHAMBER; SAID SUPPORTING MEANS ALSO BEING PROVIDED WITH A PASSAGE THERETHROUGH, AND LEVER MEANS TURNABLY JOURNALLED ON SAID SUPPORTING MEANS SO AS TO FORM A UNIT THEREWITH; SAID LEVER MEANS HAVING AN ARM EXTENDING OVER SAID PASSAGE MEANS IN CLOSE RELATIONSHIP THERETO IN ONE POSITION OF SAID LEVER MEANS AND BEING MOVABLY BY A GASEOUS FLOW THROUGH SAID PASSAGE MEANS AWAY FROM THE LATTER; SAID LEVER MEANS ALSO HAVING A CRANKED PORTION MOVABLE FROM AN EFFECTIVE POSITION CORRESPONDING TO SAID ONE POSITION, IN WHICH SAID PRESSURE RELEASE DEVICE IS EFFECTIVE TO AN INEFFECTIVE POSITION IN WHICH SAID PRESSURE RELEASE DEVICE IS IN EFFECTIVE, AND VICE VERSA. 